The present invention relates to a two-cycle engine with fuel injector capable of uniformly distributing induced air into multiple cylinders of the engine.
Recently, there is proposed a two-cycle engine with fuel injectors for improving the response during low or medium speed operation of the engine as well as high speed operation and, for improving the control of an exhaust gas emission.
For example, the Japanese Utility Model Laid-open Publication No. 58-169117 discloses a two-cycle engine with fuel injector in which fuel injection amount is determined with parameters of an intake air amount and an engine speed, and the fuel is injected from the injector with a predetermined timing.
In a two-cycle engine having two cylinders, for example, two fuel injection operate simultaneously for the respective cylinders per one revolution of the engine. The fuel is injected from the injectors of all cylinders in accordance with the intake timings of the respective cylinders. Accordingly, an air intake timing for one cylinder is not necessarily appropriate to the fuel injection timing for the other cylinder (for example, the fuel injection of the second cylinder at a crank angle of 0.degree.).
The fuel injected at a position which does not correspond to the intake timing reversely flows to the upstream side of a throttle valve when it is blown back from the cylinder. During the high or intermediate speed of the engine, the air intake inertia effect is so high that the reverse flow has less effect. However, an air cleaner element is contaminated by the blow back of the gas during the low speed operation. In addition, it is necessary to supply the additional fuel which adheres to the air cleaner element and the inner wall of the intake passage. Accordingly, the fuel efficiency becomes worse. Furthermore, the mixtures for the respective cylinders will be unevenly distributed, which results in decreasing efficiency of the exhaust emission control, the output and the acceleration performance of the engine.